module Yuki

open System

let MOD = (int 1e9) + 7

let solve n =
    let dp = Array.zeroCreate n
    dp.[0] <- 1
    dp.[1] <- 2
    dp.[2] <- 2
    for i in 3 .. (n - 1) do
        dp.[i] <- (dp.[i - 2] + dp.[i - 3]) % MOD
    dp.[n - 1]
    
let N = Console.ReadLine() |> int

N
|> solve
|> Console.WriteLine